linux-kernel - Re: [PATCH] mmc: Add new via-sdmmc host controller driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 14 Jun 2009 12:55:37 +0200
From:	Pierre Ossman <pierre@...man.eu>
To:	Harald Welte <HaraldWelte@...tech.com>
Cc:	Linux Kernel Mailinglist <linux-kernel@...r.kernel.org>,
	JosephChan@....com.tw, Bruce Chang <BruceChang@....com.tw>
Subject: Re: [PATCH] mmc: Add new via-sdmmc host controller driver

On Sun, 14 Jun 2009 14:52:56 +0800
Harald Welte <HaraldWelte@...tech.com> wrote:

> > 
> > You need to do the removal as the first step 
> 
> Thanks, I've fixed this in my tree. 
> 
> Looking at other drivers, imxmmc seems to get this wrong, too.
> 

Quite right. I suppose someone should have a look at that...

> > and you might need to explicitly kill any ongoing requests.
> 
> you mean something like the snippet in sdhci.c:
> ======
>        if (dead) {
>                 spin_lock_irqsave(&host->lock, flags);
> 
>                 host->flags |= SDHCI_DEVICE_DEAD;
> 
>                 if (host->mrq) {
>                         printk(KERN_ERR "%s: Controller removed during "
>                                 " transfer!\n", mmc_hostname(host->mmc));
> 
>                         host->mrq->cmd->error = -ENOMEDIUM;
>                         tasklet_schedule(&host->finish_tasklet);
>                 }
> 
>                 spin_unlock_irqrestore(&host->lock, flags);
>         }
> ======
> 
> Why is sdhci about the only driver that does it?  What decides if we need
> to kill ongoing requests or not?
> 

I guess I haven't kept an eye on it so the others are simply buggy.

> Also, you stated that mmc_remove_host needs to be the first step.  However,
> sdhci first kills the ongoing rquest (if "dead"), and then removes the host.
> 

Right, because the reason you need to end the request is that failure
to do so will wedge the MMC system and mmc_remove_host() will never
return.

Normally the requests will eventually be completed by interrupts coming
from the hardware, but if it got removed then that might not happen.

Rgds
-- 
     -- Pierre Ossman

  WARNING: This correspondence is being monitored by the
  Swedish government. Make sure your server uses encryption
  for SMTP traffic and consider using PGP for end-to-end
  encryption.

Download attachment "signature.asc" of type "application/pgp-signature" (199 bytes)